Stock cylinder head.
Silly Racer, Smoke is for Kids
Kent Kroeker has all kinds of sayings that revolve around the concepts of absolute reliability and consistency. Sayings like "two is one and one is none" or "grenades are powerful for a little while" are expressions learned the hard way. So if KORE knows how to turn your basic Dodge utility chassis into a Baja-1000-capable race truck, who knows how to build the powerplant for that kind vehicle? The answer is Gale Banks. Gale Banks is more familiar with the 5.9 Cummins - how to make power, how to make it clean, and how to make the engine live - than anyone in the aftermarket, period. The records Banks holds at Bonneville have stood for almost 5 years. No one has come and taken them, though many have tried. Anyone can build dyno-queen motors that make high horsepower figures for a split second, but those motors could never survive a Bonneville run let alone the rigors of a 10-mile Baja silt bed in a 1,000-mile point-to-point race.
The stock cylinder head is tested on the flow bench.
So how does Banks build Baja motors for Team KORE? Gale Banks tells how: "It's very common for most diesel tuners to make HUGE amounts of boost to brute-force the air through the engine. But if you're going to make HUGE amounts of boost, which is necessary when you have a really lousy cylinder head to force the air through the ports, it takes huge amounts of exhaust pressure to drive it. The turbocharger is driven on exhaust pressure. Making huge amounts of exhaust pressure diminishes the power output of the engine. Take some away? That's negative. Plus, it keeps the heat - the exhaust energy - in the engine and causes engine durability issues. "If you try to force-feed a Cummins motor by increasing boost and fuel without modifying the head flow, you get high temperatures and lots of smoke. There is a limit to how long an engine will live producing copious amounts of smoke and high exhaust temperatures. When a diesel is rich, it produces really high exhaust temperatures and combustion temperatures, which kills the engine. When a gasoline engine is rich, it just lays down and blubbers - it's safe. So, rich is safe with a gasoline engine; rich is dangerous with diesel.
"The key was getting air to the engine without running it rich and producing smoke. You can't port the Cummins head without machining off the intake manifold and then replacing it with one of your own. What's been going on in the aftermarket is guys build sheetmetal intake manifolds. They're square-cornered, they don't flow well, there's no science to them, but they do work better than the integral iron manifold." Banks decided to go one step further and develop an intake manifold that requires machining the stock one off the head, which is a service provided at Banks. "It allows you to go in and port the cylinder head. The manifold bolts directly to the cylinder head, and everything in a Dodge Cummins pickup that bolts to the intake manifold on the stock engine bolts to the same position on our manifold. The Banks manifold has a 4-inch inlet on it instead of a much smaller one as would be on the stock engine, and that's to allow no choke point at the inlet into the manifold. It also allows better distribution of the air forward and aft in the manifold. There's also no gasket - it's O-rings to the cylinder head, so there's no gasket to blow. You can run any amount of boost you want and you won't bulge our manifold like a lot of the sheetmetal ones do. The fabricated sheetmetal ones just kind of blow up or puff up.